1. Field
An appliance having a noise reduction device is disclosed herein.
2. Background
As technology has advanced, a variety of appliances have been recently developed to facilitate convenience at home. These appliances may be provided in homes or other spaces.
Such appliances include respective drives therein. For example, appliances, such as vacuum cleaners, dishwashers, washing machines, air conditioners, air cleaners, computers, and projectors, generate all kinds of noise, and thus, noise pollution has increasingly worsened. Accordingly, efforts to block or reduce noise generated from a variety of noise sources in modern life have continued, and strict mandatory regulations against various noise levels have been gradually increased.
Appliances now often include components to suppress or reduce noise or vibration, and in particular, sound absorbing materials are widely used to remove noise. As conventional sound absorbing materials, felt, sponge, polyurethane foam, or similar materials have been mainly used. In addition, a material, in which compression fiber, glass fiber, rock fiber, or regenerated fiber, has been impregnated with thermoplastic resin or thermosetting resin, is representative of a sound absorbing material.
FIG. 1 is a perspective view of a sound absorbing material formed by bonding porous materials. The sound absorbing material 10 of FIG. 1 is formed by bonding a first layer 11 made of a porous yarn, a second layer 12 made of a flame retarding sponge, and a third layer 13 made of polyurethane foam, which sequentially absorb sound to reduce noise.
However, the above-mentioned sound absorbing material 10 has a problem in that a sound absorbing capacity is not sufficient for low frequency noise generated by drives of various appliances. In addition, the existing sound absorbing material 10 mainly uses glass fiber or polyurethane foam, an internal structure of which has a porous form or a complicated sound propagation path, in order to promote exhaustion of sound wave energy. In a case in which the sound absorbing material 10 is glass fiber, it is legally regulated to use the sound absorbing material 10 in terms of environmental pollution due to arsenic acid, and there are disadvantages to using such a material in appliances because of weak durability and moisture resistance.
Moreover, the conventional sound absorbing material 10 requires multilayered sound absorbing materials. Therefore, in using the sound absorbing material 10 within appliances, there are problems in that a large occupation space is required and a whole weight of the appliance increases.